Coated tampon



Feb. 14, 1956 F. P. PARISH COATED TAMPON Filed May 7, 1954 Alli vINVENToR.

F/r/V/f P. /DA /Q/S United States Patent O COATED TAMPON Frank P.Parish, Taneytown, Md., assignor to Sanitary Products Corporation,Chicago, Ill., a corporation of Illinois Application May 7, 1954, SerialNo. 428,263

. 8 Claims. (Cl. 12S-285) The present invention relates to tampons and,more particularly, to an improved catamenial tampon, and to an improvedmethod of manufacturing the same.

U. S. Patents Nos. 2,340,311 and 2,440,141 to Arthur B. Donovan areexamples of the type of tampon with which this invention is particularlyconcerned. The tampon has a relatively large mass of absorbent materialthat is compressed into a relatively small volume of cylindrical form.While still under compression, the cylinder is heated to produce anironing effect, after which the entrant end is rounded off and dippedinto a solution of. a lubricant coating composition. The coating is thendried to provide a binding or retentive film which retains theunderlying compressed absorbent material in the compressed state. Thecomposition of the coating is such that it dissolves readily in the bodyuids and allows the compressed material to expand to facilitate theabsorption of a relatively large volume of the fluids. A surface-activeagent dispersed in the lilm acts on the body fluid to lower its surfacetension so that it penetrates rapidly into the film or coating and thusincreases the rate of dispersion of the film into the body uids. At thesame time, the lowering of viscosity and surface tension facilitatesabsorption of the fluids by the material of the tampon.

y It has been found that the formation of a lubricated tip on acompressed cotton tampon is an operation that may be facilitatedprovided that the end of the tampon is first coated with a primary coatso that the cotton will notabsorb the fluid which is used to form thetip. This fluid must of necessity be water soluble or water dispersibleand will be absorbed by the cotton, whichy then has a tendency to form arough tip. It is possible to apply the fluid in two steps, dryingbetween each step, but the drying operation requires time and machineryand is not as practical as the present method. To overcome thesedisadvantages it has been found preferable and it is desirable to applya substance to the cotton which prevents the fluid forming the tip frombeing absorbed by the cotton and tending to form the' end making itrough and irregular. The primary coat that is applied is preferablywater soluble of water dispersible. It can, however, consist of awater-insoluble material formed in a smooth layer over the end and ofsuch a thickness that as the cotton swells from absorption of themenstrual luid and the outer portion of the tip dissolves, this primarycoat will crack and break apart readily and not cling to the tampon soas to prevent absorption and hinder the opening ofthe end of the tampon.

It has been found that the primary coat, even if water soluble or waterdispersible, should not bind the end fibers of the cotton tampon sotightly that a long time is required to expand the tampon. It should,however, serve to lightly bind the end so that it can be shaped giving asmooth, rounded end for applying the fluid used to form the tip which isdisclosed in the Donovan patents.

It is also necessary that the primary coat be of such a consistency thatit can be readily applied, preferably ice in paste form, and then cooledto form a solid film at the time of application to the tampon. lncertain circumstances, it has been found that the primary coat may beconstituted of a powder or a waxy solid. It is preferred to apply thepowder as a powder by a spinning cup in contact with the end of thetampon and the waxy solid as a liquid just above its melting point, andthen cooling to form a solid film over the end of the tampon at the timeof application to the tampon. The waxy solid can also be applied as anemulsion which breaks when applied to .the tampon and deposits a waxyfilm. on the end of the tampon.

The preferred method is to apply a paste which is of such a consistencywhen cool that it can he forced through a small opening in a die as acontinuous ribbon in metered amounts and will cling to the vend of thetampon. The paste is then distributed over the end of the tampon by aspinning cup which shapes and` coats the tampon ends partially up thesides with the paste. The paste should be in a liquid or a semi-liquidform when hot so that the tubes used to feed the metering pump can befilled completely without the presence of entrapped air, which would bethe case if a paste or solid were used. This hot liquid then sets to apaste form when cool giving a tube completely filled. y

It is also preferred that the Vpaste be such that it will dry quickly toa solid or semi-solid sortnat it will' not penetrate the end and thusbind the cotton fibers preventing the end from expanding when ythetampon is'used.l

Furthermore, if the paste does not dry quickly, the fluid used fortipping will also penetrate and bind the end, forming a rough tip. Thedying of the primary coat can be accomplished with a blast of air eitherhot or cold, althoughrit is preferred to have a substance incorporatedin the paste that will volatilize rapidly at room temperature, leaving acoat that resists or retards the penetration of the subsequently appliedtipping fluid. The same result can be accomplished by making pastes thathave` a small proportion of liquid. v

It is an object of this inventionto provide a tampon possessingincreased advantages over known coated tampons and having meanspreventing absorption of the coating prior to its dissolution followinginsertion in a body cavity.

Another object is to provide a self-sustaining tampon of compressedabsorbent material having on its entrant end portion a shape retainingand confining layer of a paste capable of retarding absorption by t'netampon body of a subsequently applied liquid coating, for an interval oftime suicient for the subsequent coating to dry.

A further object is to provide a self-sustaining tampon of compressedabsorbent material provided on its entrant end with a covering layer ofa water-dispersible surfaceactive agent capable of lowering the surfacetension and viscosity of menstrual fluid, and which, following itsapplication, is non-aqueous at any stage prior to dispersion 1n use.

Other objects will become apparent to those skilled in the art from thefollowing description taken in conjunction with the accompanyingdrawing, in which:

Figure 1 is a perspective View of an embodiment of my invention, and

Figure 2 is an axial section through the entrant end portion of a tamponcomprising a further embodiment of the invention. Y

As illustrated in the drawing, the tampon comprises a cylindrical body 3of tightly .compressed fibrous absorbent material, preferably absorbentcotton, that has been heat treated over itsl surface to produce anironing effect whereby the surface fibers are pressed into a smooth,relatively stil skin. This ironing process imparts suftcient rigidity tothe body to make it self-sustaining. The cylindrical body is formed witha rounded entrant end and, at its opposite end, is provided with a pullstring 4 for removal.

The entrant end portion of the tampon has applied thereover a coveringlayer of water-soluble or waterdispersible material that is moistureretardant; that is, retardant to the passage therethrough of liquid ormoisture externally applied.` The material may, if desired, beimpervious, but preferably is water soluble and water dispersible. Whenapplied, the material restrains the subjacent absorbent body of thetampon against loosening and expansion from its compressed state, andretains the entrant end in rounded shape.

In the embodiment of the invention shown in Figure 2, the layer 5constitutes a supporting base for a subsequently applied coating 6. Theexterior coating 6 may have any desired characteristics. It ispreferred, however, that it be a composition falling within the scope ofthe compositions `disclosed in the illustrative examples givenhereinafter. In such case, the covering 5 is comprised of material thatis capable of retarding the passage therethrough of liquid or moisturefrom the solution of the outer coating, at least long enough to permitthe outer coating to be dried. Although it is preferred that the innercovering layer 5 be water dispersible or Water soluble, so that it canreadily dissolve in the body fluids, it is within the province of myinvention that it be insoluble or practically so. It may have anyphysical state compatible with its function; for example, a paste, aliquid of high viscosity, a wax, among others. It can be, for example, apaste of toilet soap.

A tampon provided at least on its entrant end with a single coveringlayer, as shown in Figure 1, in which the layer consists of an initiallynon-aqueous surfaceactive agent such as a soap paste, particularly apaste of white soap wetted with water, is eminently suitable for usewithout further treatment or subsequent coating. Any suitablenon-aqueous, plastic, cohesive material comprised of a surface tensiondepressant that is water dispersible or water soluble may be used;preferably it should be capable of ready application at ambienttemperatures. Material in paste form is best suited toproductionrequirements: it is of low cost, easy to prepare and apply,and is suflciently cohesive to restrain the underlying body of thetampon against loosening. Its plastic nature makes shaping a simplematter and also makes the tampon very easy to insert. It is non-aqueousprior to dispersion, and thus by its nature precludes absorption by thecompressed absorbent body of the tampon.

The materials that have been found to be satisfactory in preparing thesepastes and to coat the ends of the tampons are pastes made of soap, suchas ordinary toilet soap, and water. Y

In the preferred method of application the paste is forced through asmall opening so that it is necessary for the paste to be contained intubes from which it can be forced by a plunger operated by air pressureinto a metering pump. To ll the soaper tubes so that there is no airentrapped, the paste is softened by heating until it is a liquid massand poured into the tubes to cool and set to a paste. If the materialused for a primary coat cannot be softened to a consistency such that itwill flow into the tubes and fill them without entrapping air, it isdifcult to apply the primary coat by this method. If there are airbubbles in the paste, the metering pump will not deliver the same amountof paste for each tampon and the tampon may not be covered enough tokeep the tipping uid from penetrating into the cotton.

Although a number of pastes have been prepared from various ingredientsas mentioned previously, those made with soap and other ingredients arethe most convenient to prepare and are excellent for the intendedpurpose. Two problems have to be considered in making a paste that issatisfactory. First, the hardness which is measured with a pentrometer.If too hard, it is diicult to force the paste into the metering pump andthrough its orifice. Also, if too hard, the paste will not properly bindthe end of the tampon but will flake ot in the spinning cup giving aninsutlicient coating on the end of the tampon. The softening point isrelated to the hardness so that when a satisfactory hardness isobtained, the softening point is generally high enough to besatisfactory. Both the softening point and the hardness can be variedwithin wide limits by using different formulations.

Second, is the rate of drying of the paste after it has been applied tothe tampon. Formulations in which there is no volatile solvent or a salthave not proven satisfactory using the present method of application.This is because there is no forced drying of the primary coat. Withoutforced drying the pastes that are not completely satisfactory for thepresent method penetrate the end of the tampon binding the cottonfibers. together tightly and causing the tip to swell to some extent dueto absorption of moisture from the paste. When forced drying is used,this does not occur with these formulations.

ILLUSTRATIVE EXAMPLES OF PRIMARY COAT- ING FORMULATIONS Soap and watersolutions Pastes made of' soap and water require a long drying time atroom temperature and cause some swelling of the end of the tampon unlessdried in a hot air blast. EX cept for this point, these pastes can beapplied by the method previoulsy described. These pastes range incomposition within the following limits:

Percent Soap 20-45 Water 55-80 Percent Soap 45-75 Water 25-55Satisfactory results have been obtained by coating a tampon with a pasteof the following composition:

Soap About 25%. Water About 75%. Softening point About4l C.

Some examples of soap formulations employed in the present inventionare:

EXAMPLE I Percent Limits .85 .93 15.45 to 16.45. 19 3.84 to 4.20. .63 51.62 H10 14. 30 Maximum glyecrine content 0. 45

EXAMPLE II Percent Limits N530 6.54 Factor 1.97 Hz 13.27 12.67 to 14.30.

The factor included in each type of soap contains numerous buildersdepending on the particular product.

Although the present invention has been described in conjunction withpreferred embodiments, it is to be understood that modifications andvariations may be resorted to without departing from the spirit andscope of the invention, as those skilled in the art will readilyunderstand. Such modifications and variations are considered to bewithin the purview and scope of the invention and appended claims.

I claim:

1. An improved catamenial tampon comprising a body of compressedabsorbent material having, at least on its entrant end, a driedinitially liquid iilm containing a water-dispersible, surface activeagent capable of lowering the surface tension of menstrual iiuid, andbeneath said film a covering layer of material blocking the passage ofmoisture to the subjacent body of the tampon.

2. An improved catamenial tampon comprising a body of compressedabsorbent material having, at least on its entrant end, a coating of adried, initially liquid film containing a water-dispersible,surface-active agent capable of lowering the surface tension ofmenstrual fluid, and a covering layer under said coating, said coveringlayer comprising material retardant to the passage therethrough ofliquid from the ilm for a period of time substantially suicient for thefilm to dry.

3. An improved catamenial tampon comprising a body of compressedabsorbent material having, at least on its entrant end, a driedinitially liquid film containing a water-dispersible agent capable oflowering the surface tension of menstrual fluid, and beneath said lm acoating of material retardant to the passage therethrough of liquid fromthe film for a period of time substantially sufficent for the lm to dry.

4. An improved catamenial tampon comprising a body of compressedabsorbent material having, at least on its entrant end, a driedinitially liquid film containing a water-dispersible, surface-activeagent capable of lowering the surface tension of menstrual Huid, andbeneath said film a covering layer of a paste retardant to the passageof liquid.

5. An improvedcatamenial tampon comprising a body of compressedabsorbent material having, at least on its entrant end, a driedinitially liquid film containing a water-dispersible, surface-activeagent capable of lowering the surface tension of menstrual fluid, andbeneath said film a covering layer of a paste retardant to the passageof liquid therethrough, said paste comprising soap.

6. An improved catamenial tampon comprising a body of compressedabsorbent material having, at least on its entrant end, a driedinitially liquid film containing a surface tension depressant formenstrual fluid absorbable in the compressed material of the tamponuntil dried, and the body of the tampon beneath said film having acovering layer binding the tampon in its compressed state and preventingabsorption of matter from said film prior to drying thereof.

7. Method of tipping a catamenial tampon with a solution of materialthat forms a lubricant film when dried, which comprises, precoating atleast the entrant end portion of thetampon with a covering materialcapable of preventing absorption of the film forming solution into thematerial of the tampon, applying the solution of film forming materialover and upon the covering material, and -drying the applied solution toprovide a film tip in situ.

8. In the method of claim 7, said precoat covering material consistingof a water-dispersible paste of soap.

References Cited in the le of this patent UNITED STATES PATENTS 706,778Pond Aug. 12, 1902 2,092,427 Ross Sept. 7, 1937 2,340,311 Donovan Feb.1, 1944 2,440,141 Donovan Apr. 20, 1948

1. AN IMPROVED CATAMENIAL TAMPON COMPRISING A BODY OF COMPRESSEDABSORBENT MATERIAL HAVING, AT LEAST ON ITS ENTRANT END, A DIREDINITIALLY LIQUID FILM CONTAINING A WATER-DISPERSIBLE, SURFACE ACTIVEAGENT CAPABLE OF LOWER ING THE SURFACE TENSION OF MENSTRUAL FLUID, ANDBENEATH SAID FILM A COVERING LAYER OF MATERIAL BLOCKING THE PASSAGE OFMOISTURE TO THE SUBJACENT BODY OF THE TAMPON.